1. Field of the Invention
The present invention relates to a treating liquid employed in the manufacture of a semiconductor device, and to a method for manufacturing a semiconductor device. In particular, the present invention relates to a treating liquid employed in the post-treatment for Chemical Mechanical Polishing (CMP), and to a method for manufacturing a semiconductor device using this treating liquid.
2. Description of the Related Art
In recent years, to meet the trend to further enhance the integration of LSI, the techniques to further refine the wirings are now being rapidly advanced in the manufacture of LSIs. Additionally, in order to alleviate the retardation of wiring RC, it is considered imperative to employ a novel material. Under the circumstances, it is now tried to employ Cu which is low in electric resistance (ρ: 1.8 μΩcm) as a conductive material, and to employ an insulating film having low relative dielectric constant (k: <2.5) as an electric insulating material.
Cu wirings (wirings made of Cu) are formed, in most cases, as damascene wirings by using a CMP technique. Since an electric conductive material located between wirings can be removed in polishing by a CMP, it is possible to obtain a wiring relatively free from short-circuits as compared with the wiring such as the conventional Al wirings formed by RIE.
After this CMP treatment, residual materials such as dust (residual polishing particles and residual shavings) and unreacted slurry unavoidably remain on the surfaces of the insulating film and of the wirings. These residual materials have been conventionally removed by using a washing liquid containing a chelate complex-forming agent and a surfactant. However, as the intervals between wirings are increasingly narrowed, it now becomes more difficult to employ this conventional method for coping with the removal of these residual materials.
Since the intervals of wirings required for the semiconductor device of the next generation will be 0.1 μm or less, a small quantity of such a very fine residual material that has been conventionally not considered to raise any substantial problem may become a cause for the generation of defective wirings, such as short-circuits between wirings, or deterioration in the withstand voltage of an insulating film.
Further, since most insulating films having a low relative dielectric constant contain an organic component, the surface of such insulating films is hydrophobic and hence poor in wettability to water. As a result, dust is easily adsorbed onto the surface of the insulating film during the CMP treatment or during the washing after the CMP treatment. Moreover, the dust thus adsorbed cannot be removed, which is one of the problems preventing wirings from being electrically isolated from each other. The insulating film having a low relative dielectric constant is also accompanied with a defect that scratches are more likely to be formed thereon.